Lathe technology has been used in many applications, and typically involves a machine on which a workpiece such as wood, metal, glass or other material is spun and shaped by either hand or tool. As a result, various different lathe systems exist for accommodating different types of materials and performing different types of operations. In particular, in the field of glass shaping and glass blowing, various types of lathes have been developed in order to perform various different operations in shaping and/or building glass devices. These lathe systems typically include a pair of chucks disposed at opposite ends of the lathe and which are adjustable in order to hold glass devices between the two chucks. In addition, a heating element is moveable between the two chucks for heating the glass somewhere along its longitudinal axis such that the glass may be shaped as is desired for the particular application. Further, the chucks may be rotated, thereby rotating the glass structure connected between the two chucks. This rotation causes a uniform area of heat from the heating element to be applied to the rotating glass in the area adjacent the heating element.
The lathe systems available in the prior art, however, have certain limitations. One key limitation arises from the use, or attempted use, of increased temperatures from the heating element. In particular, increased temperatures may have adverse consequences on various components of the lathe. One particular example is the limited amount of heat that prior art chuck inserts can withstand. More particularly, certain applications requiring high temperatures have until the present invention been impossible to perform using a lathe because the chuck inserts would fail (e.g. melt and/or break), thereby preventing the use of the lathe.
Another limitation arises when an increased temperature application is combined with an increased weight of the device being held by the lathe chucks. For example, if a particular glass application involves a relatively heavy piece of glass, and also requires large temperatures from the heating element, the operation of the lathe may become inaccurate and/or unsafe. In particular, as the lathe is rotated and the temperature of the heating element is increased, the glass device held by the chucks transmits a great deal of this increased temperature to the chucks themselves. Still further, the chucks may also be brought into close proximity with the heating element, thereby directly exposing them to the increased heat. The chuck systems currently existing in the prior art, however, are incapable of withstanding temperatures above a certain limit. As a result, the glass member held by the chucks may not be properly supported and, therefore, the desired operation on the glass member may become very difficult to achieve. Indeed, for temperatures above a certain range, it has been impossible to use the prior art lathe systems because the components of the chucks are simply unable to withstand the temperature and, therefore, are unable to properly support the glass member held by the chucks.
One very troubling example of the above limitations arises in the process of fusing a flange onto a cylindrical quartz tube. In order to bond the flange to the tube using a lathe system, a temperature on the order of 1700.degree. C. would be necessary. The prior art lathe systems, however, utilize chuck components made of either transite or stainless steel. Neither of these materials is capable of withstanding the 1700.degree. C. temperatures and, therefore, the lathe system has been unusable for purposes of fusing the flange onto the quartz tube. In particular, a transite material in the chuck system would burn and contract and, therefore, could release the glass tube, thereby causing severe damage to the tube and creating a very dangerous atmosphere. Alternatively, the use of a stainless steel chuck system in this high temperature environment would cause the stainless steel to expand due to the increased temperature, and would likely cause the quartz tube to break. Therefore, this too is an unusable solution and a dangerous approach. Further, in each instance the increased likelihood of damage to the quartz tube is also reflected as an increased cost in the fusing of flanges onto glass tubes.
As a result of the limitations of the prior art, in certain applications where extremely high heat levels are used in combination with the formation of glass structures, persons skilled in the art have been forced to manually work with the glass rather than being able to use the lathe system at all. In particular, one attempted solution in the prior art required an operator to manually fuse a flange onto a quartz tube. Thus, some type of device was required in order to hold the flange immediately abutting the tube while the operator fused the flange to the tube by hand. This approach, however, has numerous limitations. For example, this technique requires a great deal of time in performing the various steps to accomplish the purpose of attaching the flange to the tube. In particular, first the flange must be positioned immediately next to the tube. Second, a quartz fuse rod must be used to run or tack a bead of quartz between the flange and the tube. Third, the bead has to be fused again in order to seal the flange to the tube. Obviously, this multi-step process requires a great deal of time and resources. As yet another limitation, the above-stated tacking and fusing steps may only be performed over a circumferential distance on the order of two inches. Many tubes have circumferences on the order of 8 to 14 inches and, therefore, this limitation requires a large expenditure of time. If the operator attempts to go beyond this approximate two inch limitation, there is an increased likelihood that either the tube or flange would be destroyed and, therefore, the entire process would have to be recommenced. In addition, the destruction of either the tube or the flange may be dangerous, and has obvious economic consequences as well.
Therefore, a need has arisen for an improved lathe system and methodology which permits operation in increased temperature applications and minimizes the time and expense incurred in performing the desired operation.